What is the best way to print paper checks for unpaid bills?

Hello there. I'd like to take it from here to share some details and steps to help you print unpaid bills in QuickBooks Online (QBO).

In QBO, the option to print a check for unpaid bills is unavailable. As a workaround, you can right-click the bill you want to print and select the Print button. Here's how:

1. Select the Expenses menu and go to Bills.
2. Next, select the Unpaid tab.
3. From there, look for the unpaid bill you want to print.
4. Click it to open.
5. Once opened, right-click the page and click Print.
6. Then, select the Print button.

For reference, check out this article: Enter and manage bills and bill payments in QuickBooks Online. 

Additionally, you can also run and customize the Transactions List by Vendor report to see all the bills of your vendors. I'll guide you on how:

1. Navigate to the Reports menu.
2. From the search bar, type Transactions List by Vendor.
3. Customize the report depending on the details you need. 
4. Select Run Report. 

You can always post here if you need further help with printing your unpaid bills. I'm always around to provide assistance.